cec: refine CEC enable/disable logic.

CEC is enabled in CEC HAL by default. That should still be disabled
after reboot.

And if CEC is disabled, when enable it, we should enable CEC too
as well enable system control.

BUG: 110175546

Test: local test.
Change-Id: I4b110c88c719e07bf2cc884e0682e5ab73359fd4
(cherry picked from commit 45d424c08935384e9cc9b78a69a27a30637d5454)
1 file changed